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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

using System;
using System.Collections;
using Velocity4Net.Errors;
using Velocity4Net.Runtime.Logging;
namespace Velocity4Net.Runtime.Parse.AST
{

    /**
     * GetExecutor that is smart about Maps. If it detects one, it does not
     * use Reflection but a cast to access the getter. 
     *
     * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
     * @version $Id: MapGetExecutor.java 799457 2009-07-30 22:10:27Z nbubna $
     * @since 1.5
     */
    public class MapGetExecutor
            : AbstractExecutor
    {
        private String property;

        public MapGetExecutor(Log log, Type clazz, String property)
        {
            this.log = log;
            this.property = property;
            Discover(clazz);
        }

        protected void Discover(Type clazz)
        {
            if (property != null && typeof(IDictionary).IsAssignableFrom(clazz))
            {
                try
                {
                    setMethod(typeof(IDictionary).GetMethod("Item", new Type[] { typeof(Object) }));
                }
                /**
                 * pass through application level runtime exceptions
                 */
                catch (ApplicationException e)
                {
                    throw e;
                }
                catch (System.Exception e)
                {
                    String msg = "Exception while looking for get('" + property + "') method";
                    log.error(msg, e);
                    throw new VelocityException(msg, e);
                }
            }
        }

        public override Object Execute(Object o)
        {
            return ((IDictionary)o)[property];
        }
    }
}